A lightvessel, or lightship, is a ship that acts as a lighthouse. They are used in waters that are too deep or otherwise unsuitable for lighthouse construction. Although some records exist of fire beacons being placed on ships in Roman times, the first modern lightvessel was off the Nore sandbank at the mouth of the River Thames in London, England, placed there by its inventor Robert Hamblin in 1734. The type has become largely obsolete; lighthouses replaced some stations as the construction techniques for lighthouses advanced, while large, automated buoys replaced others.
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Construction began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. However, though its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit.
The Thomas Point Shoal Light, also known as Thomas Point Shoal Light Station, is a historic lighthouse in the Chesapeake Bay on the east coast of the United States, and the most recognized lighthouse in Maryland. It is the only screw-pile lighthouse in the bay which stands at its original site. The current structure is a 1½ story hexagonal wooden cottage, equipped with a foghorn as well as the light.
Ambrose Light, often called Ambrose Tower, was the light station at the convergence of several major shipping lanes in Lower New York Bay, including Ambrose Channel, the primary passage for ships entering and departing the Port of New York and New Jersey.
The unmanned reef lights of the Florida Keys were navigational aids erected near the Florida Keys between 1921 and 1935. They were intended to mark local hazards and did not need to be visible for as far as the reef lights that were erected near the Keys during the 19th century. By the time the lights in this list were erected, older lighthouses were being automated, and these new lights were designed to be automated from the start. The lights resembled the older reef lights in having a wrought iron skeletal pyramidal structure on a screw-pile foundation. They all originally had lanterns on their peaks, so that they looked like smaller versions of the older reef lights, but had no keeper's quarters.
Sandy Point Shoal Light is a brick three story lighthouse on a caisson foundation that was erected in 1883. It lies about 0.6 mi (0.97 km) off Sandy Point, north of the Chesapeake Bay Bridge, from whose westbound span it is readily visible.
New Point Comfort Light is a lighthouse in the Virginia portion of the Chesapeake Bay, United States, off the tip of the Middle Peninsula. Finished in 1804, it is the third-oldest surviving light in the bay, and the tenth-oldest in the United States.
Thimble Shoal Light is a sparkplug lighthouse in the Virginia portion of Chesapeake Bay, north of the Hampton Roads channel. The third light at this location, it is listed on the National Register of Historic Places.
The Windmill Point Light was a lighthouse located at the mouth of the Rappahannock River.
Smith Point Light is a caisson lighthouse in the Virginia portion of the Chesapeake Bay at the mouth of the Potomac River. It was added to the National Register of Historic Places in 2002.
Chesapeake Light is an offshore lighthouse marking the entrance to the Chesapeake Bay. The structure was first marked with a lightship in the 1930s, and was later replaced by a "Texas Tower" in 1965. The lighthouse was eventually automated and was used for supporting atmospheric measurement sites for NASA and NOAA. Due to deteriorating structural conditions, the lighthouse was deactivated in 2016. At the time, it was the last remaining "Texas Tower" still in use due to obsolescence.
The Rock of Ages Light is a U.S. Coast Guard lighthouse on a small rock outcropping approximately 2.25 miles (3.62 km) west of Washington Island and 3.5 miles (5.6 km) west of Isle Royale, in Eagle Harbor Township, Keweenaw County, Michigan. It is an active aid to navigation.
The Brenton Reef Light was a Texas tower lighthouse at the entrance to Narragansett Bay, Rhode Island, United States, south of Beavertail Point. Erected to replace a lightship in 1962, it was decommissioned in 1989 due to its deteriorating condition.
The Brandywine Shoal Light is a lighthouse on the north side of the ship channel in Delaware Bay on the east coast of the United States, west of Cape May, Cape May County, New Jersey, United States. It was the site of the first screw-pile lighthouse in the United States.
Diamond Shoal Light is an inactive offshore lighthouse marking Diamond Shoals off Cape Hatteras.
The Musselbed Shoals Light was a lighthouse which once stood in Narragansett Bay at the west entrance to Mount Hope Bay, south of Bristol Point. As with many Rhode Island lights, it was a casualty of the New England Hurricane of 1938.
The Peshtigo Reef Light is a lighthouse in Marinette County, Wisconsin, United States, offshore in lower Green Bay. Constructed in 1936 to replace a lightship, it remains in service.
The Grays Reef Light is a lighthouse located in northeastern Lake Michigan, 3.8 miles (6.1 km) west of Waugoshance Island in Bliss Township, Michigan. It was listed on the National Register of Historic Places in 2005.
The Ship Shoal Light is a screw-pile lighthouse located in the Gulf of Mexico southwest of the Isles Dernieres off the coast of Louisiana. It is currently abandoned.
